1. Field of the Invention
The present invention is broadly concerned with improved mobile, remote controlled robots and robotic assemblies which can be used for the inspection of, or operations on or about, upright members such as bridge piers and abutments or generally horizontal or obliquely oriented members such as pipelines. More particularly, it is concerned with such mobile robots which have independently shiftable traction elements pivotally coupled to the robot body along with a carriage pivotally coupled to the body and adapted to support an operating unit such as a visual imaging device. In preferred forms, two or more such robots can be used in conjunction with a tether assembly operatively coupled to the respective robots and extending around the member to be inspected or otherwise worked upon. Control means is provided for selectively adjusting the tension of the tether assembly in order to hold the individual robots in tractive engagement with the member.
2. Description of the Prior Art
In order to maintain the safety of bridges, it is necessary to periodically inspect both the visible superstructure and underwater substructure of the bridges. It is obviously much more difficult to properly inspect the underwater portions of bridges and similar structures, owing to the harsh environment affecting the mobility and visibility of the inspectors. Generally speaking, underwater bridge inspections are presently carried out by divers, necessitating use of highly skilled inspectors knowledgeable of diving equipment, safety requirements, communication techniques and the inherent dangerous conditions of such inspections. Thus, the inspector must be capable of working under adverse water conditions such as deep, cold water and poor visibility (indeed under certain circumstances a diver/inspector can only use tactile methods of inspection) and have a comprehensive knowledge of the design and construction features of bridge substructures. A qualified inspector must also be able to properly interpret and report what is observed, be able to recognize structural deficiencies and to identify incipient problems so that preventive action can be taken.
In an effort to eliminate or minimize the need for diver/inspectors, sophisticated equipment such as echosounders, ultrasonic thickness gauges and remotely operated vehicles (ROV) have been used. ROVs have assumed an importance in the marine industry, and off-shore petroleum and salvage operations have increasingly relied upon information supplied by ROV cite investigations to aid in planning and execution of underwater tasks. Initially, ROV design tended to be generic, i.e., diverse applications were sought or a technology developed to provide general inspection and simple task performance capabilities. However, while prior ROVs have found utility in certain contexts, the inability of these fairly expensive systems to operate under strong currents in streams and rivers seriously limits their use for underwater inspection of bridges.
Surface inspection and/or work is also often required with horizontal or obliquely oriented bodies such as large pipelines. These pipelines extend for considerable distances through many types of terrains and conditions, and there is also a need for an improved system allowing remote control inspection or work upon these types of structures.
There is accordingly a need in the art for improved mobile robots and multiple-robot assemblies which can be used for the inspection of members or bodies such as bridge pillars, supports and pipelines, even under the sometimes extremely adverse conditions encountered in these environments.